Method and system for determining receiver power for required bit error rate

Abstract

A method and system for determining a receiver power for a required bit error rate (BER) in an optical communication systems is disclosed. A signal is transmitted using an initial transmitter power and is received at a receiver. A BER contour diagram is created by measuring high BER values and approximating low BER values from the high BER values. The optimum decision threshold and / or sampling phase is determined from the contour diagram and the BER is calculated at the optimum decision threshold and / or at the optimum sampling phase. If the calculated BER is not close to or equal to the required BER, the transmitter power is adjusted until the calculated BER is close to or equal to the required BER. The receiver power is then calculated from the transmitter power or directly measured from the received signal.

Description

RELATED APPLICATION [0001] This application is related to an application entitled “BIT ERROR RATE CONTOUR-BASED OPTIMUM DECISION THRESHOLD AND SAMPLING PHASE SELECTION”, attorney docket number 185940 / US, filed concurrently.TECHNICAL FIELD [0002] The present invention relates generally to optical communication systems, and more specifically to a method and system for determining receiver power for a required bit error rate (BER). BACKGROUND OF THE INVENTION [0003] In optical communication systems, it is often desirable to determine the minimum power at a receiver to achieve a required or a specified bit error rate (or bit error ratio, where the bit error ratio is defined as the number of erroneously transmitted bits divided by the number of correct bits). Many optical communication systems must operate within a specified BER. The BER is generally dependent, among others, on the receiver power. The BER decreases as the receiver power is increased and the BER increases as the receiver ...

AI Technical Summary

Benefits of technology

[0015] The present invention is directed to a method and system for determining a receiver power for a required bit error rate (BER) in optical communication systems. According to one aspect of the invention, a BER contour diagram is created by measuring high BER values and approximating low BER values from the high BER values. The low BER values are approximated using error functions. The optimum decision threshold is determ

Problems solved by technology

The nonlinear effects shift the optimum decision threshold for a sampling phase away from the mid point between the marks and the spaces causing the optimum BER to be difficult to measure.

Also, if the required BER is low, it may require a long time to determine the minimum power required at the receiver, which is typically specified during system or equipment calibration.

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